Heartwater
Cowdriosis, Malkopsiekte,
Pericardite Exsudative Infectieuse,
Hidrocarditis Infecciosa,
Idropericardite Dei Ruminanti
Overview
• Organism
• Economic Impact
• Epidemiology
• Transmission
• Clinical Signs
• Diagnosis and Treatment
• Prevention and Control
• Actions to Take
Center for Food Security and Public Health, Iowa State University, 2011
The Organism
Ehrlichia ruminantium
• Anaplasmataceae
– Cytoplasm of capillary
endothelial cells of
infected animals
– Coccoid, occasional rings
– Clumps of a few to several
thousand organisms
– Red/purple to blue
with Giemsa stain
Center for Food Security and Public Health, Iowa State University, 2011
Importance
History
• 1830: South Africa – sheep
• 1898: Transmissibility
• 1900: Tropical bont tick vector
• 1925: Caused by Rickettsial agent
• 1980: Found in Western Hemisphere
• 1992 and 1997: Florida-imported
vector ticks
Center for Food Security and Public Health, Iowa State University, 2011
Economic Impact
• Zimbabwe
– US $5.6 million annual losses
– Acaricide, milk loss, treatment cost
• Serious threat to the United States
– Caribbean Islands with infected ticks
– Migratory cattle egrets
– Susceptible cattle and deer population
• 40% to 100% death in U.S. expected
Center for Food Security and Public Health, Iowa State University, 2011
Epidemiology
Geographic Distribution
• Sub-Saharan Africa
• The Caribbean Islands
– Puerto Rico,
Guadeloupe, Barbados,
St. Vincent, Antigua,
Marie, Galante
• Not reported in Asia
• Tick introduction into
U.S. possible
Center for Food Security and Public Health, Iowa State University, 2011
Morbidity/Mortality
• Susceptible ruminants
• Morbidity: Approaches 100%
• Mortality:
– 6% in Persian or Afrikander sheep
– 60% in Cattle
– 80% in Merino sheep and Angora goats
Center for Food Security and Public Health, Iowa State University, 2011
Transmission
Animal Transmission
• Vector-borne
• Amblyomma ticks
• Larvae and nymphs infected
– From infected animals
• Animal inoculation
– Infected nymphs and adult ticks
– Mammals, birds, and reptiles
Center for Food Security and Public Health, Iowa State University, 2011
Animal Transmission
• Cow to calf transmission
– Via colostrum
• Tick spread
– Cattle egret
– Helmeted guinea fowl
• Natural reservoirs
– Blesbok
– Wildebeest
Center for Food Security and Public Health, Iowa State University, 2011
Animals and Heartwater
Affected Species
• Severe disease
– Cattle, sheep, goats, water buffalo
– White-tailed deer (experimentally)
– Lechwe
• Mild disease
– Indigenous African breeds of sheep
and goats
• Inapparent disease
– Blesbok, wildebeest, eland, springbok
Center for Food Security and Public Health, Iowa State University, 2011
Clinical Signs
• Incubation period: 14 to 28 days
– Experimental intravenous inoculation
• Sheep and goats: 7 to 10 days
• Cattle: 10 to 16 days
• Four forms of disease
– Peracute (rare)
– Acute (most common)
– Subacute (rare)
– Mild or subclinical
Center for Food Security and Public Health, Iowa State University, 2011
Clinical Signs: Acute
• Most common form
• Sudden fever (107oF)
• Inappetence, depression
• Tachypnea, respiratory distress
• Nervous signs
– Chewing movements, eyelid twitching,
tongue protrusion, circling, paddling
• Death in 1 week
Center for Food Security and Public Health, Iowa State University, 2011
Clinical Signs: Subclinical
• “Heartwater fever”
• Breeds with resistance
or partial immunity
• Asymptomatic
• Transient fever
Center for Food Security and Public Health, Iowa State University, 2011
Clinical Signs: Other Forms
• Peracute
– Sudden death
– Fever, severe respiratory distress,
convulsions, ± severe diarrhea
• Subacute
– Prolonged fever, coughing, edema of
lungs, mild incoordination
– Recovery or death in 1 to 2 weeks
Center for Food Security and Public Health, Iowa State University, 2011
Post Mortem Lesions
• Hydropericardium
• Hydrothorax
• Ascites
• Pulmonary and mediastinal edema
• Petechiae and ecchymoses
– Mucosal and serosal surfaces
– GI tract, esp. abomasum
• Congestion and edema in the brain
Center for Food Security and Public Health, Iowa State University, 2011
Hydropericardium
Hydrothorax
Center for Food Security and Public Health, Iowa State University, 2011
Differential Diagnosis
• Anthrax (peracute; sudden death)
• Acute form
– Rabies
– Tetanus
– Meningitis or encephalitis
– Babesiosis
– Cerebral typanosomiasis
– Theileriosis
– Poisons
Center for Food Security and Public Health, Iowa State University, 2011
Sampling
• Before collecting or sending any
samples, the proper authorities
should be contacted
• Samples should only be sent under
secure conditions and to authorized
laboratories to prevent the spread of
the disease
Center for Food Security and Public Health, Iowa State University, 2011
Diagnosis
• Clinical signs
– Fever, respiratory
distress, sudden death
– Presence of
Amblyomma ticks
• Laboratory Tests
– Microscopic identification
organism
– PCR, IFA, ELISA
Center for Food Security and Public Health, Iowa State University, 2011
Treatment
• Early stage
– Oxytetracycline
• Late stage
– When neurological
signs occur
– Usually futile
Center for Food Security and Public Health, Iowa State University, 2011
Heartwater in Humans
Prevention
and Control
Recommended Actions
• IMMEDIATELY notify authorities
• Federal
– Area Veterinarian in Charge (AVIC)
http://www.aphis.usda.gov/animal_health/area_offices/
• State
– State veterinarian
http://www.usaha.org/StateAnimalHealthOfficials.pdf
• Quarantine
Center for Food Security and Public Health, Iowa State University, 2011
Recommended Actions
• Quarantine
– All wild ruminants imported from Africa
• PCR for E. ruminantium
– All wild ungulates, birds, and reptiles
imported to U.S.
• Examine for ticks
Center for Food Security and Public Health, Iowa State University, 2011
Prevention
• Tick control program
– Acaricides
• Importation control and monitoring
– Infected wildlife or ticks
• The Caribbean Amblyomma Program
−English and Dutch-speaking islands
• POSEIDOM Vétérinaire Programme
−French-speaking islands
Center for Food Security and Public Health, Iowa State University, 2011
Vaccination
• Attenuated E. ruminantium
– BALL3-strain serial passage
– Confers solid immunity
• Universally effective vaccine
not developed
Center for Food Security and Public Health, Iowa State University, 2011
Additional Resources
• World Organization for Animal Health
(OIE)
– www.oie.int
• U.S. Department of Agriculture (USDA)
– www.aphis.usda.gov
• Center for Food Security and Public Health
– www.cfsph.iastate.edu
• USAHA Foreign Animal Diseases
(“The Gray Book”)
– www.usaha.org/pubs/fad.pdf
Center for Food Security and Public Health, Iowa State University, 2011
Acknowledgments
Development of this presentation
was funded by grants from
the Centers for Disease Control and Prevention,
the Iowa Homeland Security and Emergency
Management Division, and the Iowa Department
of Agriculture and Land Stewardship
to the Center for Food Security and Public
Health at Iowa State University.
Authors: Babsola Olugasa, DVM, MS; Anna Rovid Spickler, DVM, PhD; Radford Davis,
DVM, MPH, DACVPM
Reviewers: Bindy Comito Sornsin, BA; Katie Spaulding, BS; Jared Voge, MS; Kerry
Leedom Larson, DVM, MPH, PhD
Center for Food Security and Public Health, Iowa State University, 2011